U.S. patent application number 16/994400 was filed with the patent office on 2020-12-03 for apparatus for preventing backside peeling defects on semiconductor wafers.
This patent application is currently assigned to TAIWAN SEMICONDUCTOR MANUFACTURING CO., LTD.. The applicant listed for this patent is TAIWAN SEMICONDUCTOR MANUFACTURING CO., LTD.. Invention is credited to Wei-Jen CHEN, Yen-Yu CHEN, Yi-Chen CHIANG, Chang-Sheng LEE, Wei-Chen LIAO, Tsang-Yang LIU, Wei ZHANG.
Application Number | 20200381287 16/994400 |
Document ID | / |
Family ID | 1000005019920 |
Filed Date | 2020-12-03 |
United States Patent
Application |
20200381287 |
Kind Code |
A1 |
CHEN; Yen-Yu ; et
al. |
December 3, 2020 |
APPARATUS FOR PREVENTING BACKSIDE PEELING DEFECTS ON SEMICONDUCTOR
WAFERS
Abstract
An apparatus includes a susceptor and a non-reactive gas source.
The susceptor has through holes and a wafer support surface. Each
through hole includes a lift pin and a lift pin head. The lift pin
has a vertical degree of motion in the through hole to lift up or
place a wafer on the susceptor. The lift pin head has at least one
flow channel structure running from its first surface at least
partially exposed to a bottom side of the susceptor through its
second surface exposed to a top side of the susceptor wherein the
lift pin. The non-reactive gas source is configured to flow a gas
to a backside of the wafer through the flow channel structure
through the bottom side of the susceptor.
Inventors: |
CHEN; Yen-Yu; (Taichung
City, TW) ; CHEN; Wei-Jen; (Taichung City, TW)
; CHIANG; Yi-Chen; (Taichung City, TW) ; LIU;
Tsang-Yang; (Changhua County, TW) ; LEE;
Chang-Sheng; (Hsinchu City, TW) ; LIAO; Wei-Chen;
(Nantou County, TW) ; ZHANG; Wei; (Hsinchu County,
TW) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
TAIWAN SEMICONDUCTOR MANUFACTURING CO., LTD. |
Hsinchu |
|
TW |
|
|
Assignee: |
TAIWAN SEMICONDUCTOR MANUFACTURING
CO., LTD.
Hsinchu
TW
|
Family ID: |
1000005019920 |
Appl. No.: |
16/994400 |
Filed: |
August 14, 2020 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
16230765 |
Dec 21, 2018 |
10748806 |
|
|
16994400 |
|
|
|
|
13929297 |
Jun 27, 2013 |
10163676 |
|
|
16230765 |
|
|
|
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H01L 21/68742
20130101 |
International
Class: |
H01L 21/687 20060101
H01L021/687 |
Claims
1. An apparatus, comprising: a susceptor having a wafer support
surface and a hole extending downwards from the wafer support
surface of the susceptor; a lift pin movably received in the hole
of the susceptor; a lift pin head coupled with the lift pin and
having a lower portion and an upper portion, wherein the upper
portion of the lift pin head has a bottom surface extending
laterally from a top end of a sidewall of the lower portion of the
lift pin head, a top surface opposite to the bottom surface of the
upper portion of the lift pin head, a sidewall extending downwards
from the top surface of the upper portion of the lift pin head, and
a cut portion extending from the bottom surface of the upper
portion of the lift pin head to the sidewall of the upper portion
of the lift pin head; and a non-reactive gas source in fluid
communication with the hole of the susceptor.
2. The apparatus of claim 1, wherein the upper portion of the lift
pin head is wider than the lower portion of the lift pin head.
3. The apparatus of claim 1, wherein the cut portion of the upper
portion of the lift pin head and a sidewall of the hole define a
passage that is in fluid communication with the non-reactive gas
source.
4. The apparatus of claim 1, wherein the sidewall of the upper
portion of the lift pin head faces and is spaced apart from a
sidewall of the hole.
5. The apparatus of claim 1, wherein the lift pin is in contact
with the bottom surface of the upper portion of the lift pin
head.
6. The apparatus of claim 1, wherein the bottom surface of the
upper portion of the lift pin head is at least partially exposed by
the hole of the susceptor.
7. An apparatus, comprising: a susceptor having a wafer support
surface and a hole extending downwards from the wafer support
surface of the susceptor; a lift pin movably received in the hole
of the susceptor; a lift pin head coupled with the lift pin and
having a lower portion and an upper portion, wherein the upper
portion of the lift pin head has a bottom surface extending
laterally from a top end of a sidewall of the lower portion of the
lift pin head and a slanting surface extending upwards from the
bottom surface of the upper portion of the lift pin head; and a
non-reactive gas source in fluid communication with the hole of the
susceptor.
8. The apparatus of claim 7, wherein a top edge of the slanting
surface of the upper portion of the lift pin head is curved.
9. The apparatus of claim 7, wherein the upper portion of the lift
pin head has a sidewall at least partially extending upwards from a
top edge of the slanting surface of the upper portion of the lift
pin head to a top surface of the upper portion of the lift pin
head.
10. The apparatus of claim 9, wherein the slanting surface of the
upper portion of the lift pin head is slanted with respect to the
sidewall of the upper portion of the lift pin head.
11. The apparatus of claim 7, wherein the slanting surface of the
upper portion of the lift pin head is slanted with respect to the
bottom surface of the upper portion of the lift pin head.
12. The apparatus of claim 7, wherein the hole of the susceptor has
a bottom opening on a bottom of the susceptor, and the bottom
surface of the upper portion of the lift pin head is over and
vertically overlaps the bottom opening of the hole of the
susceptor.
13. The apparatus of claim 7, wherein the lift pin head is
detachably coupled with the lift pin.
14. An apparatus, comprising: a susceptor having a wafer support
surface and a hole extending downwards from the wafer support
surface of the susceptor; a non-reactive gas source configured to
apply an non-reactive gas to the hole of the susceptor; a lift pin
movably received in the hole of the susceptor; and a lift pin head
coupled with the lift pin and having a lower portion and an upper
portion, wherein the upper portion of the lift pin head has a
surface opposite and slanted with respect to a sidewall of the hole
of the susceptor, and said surface of the upper portion of the lift
pin head opposite and slanted with respect to the sidewall of the
hole of the susceptor and the sidewall of the hole of the susceptor
define a passage that allows the non-reactive gas to flow
therethrough.
15. The apparatus of claim 14, further comprising an inner chamber
enclosing the wafer support surface of the susceptor.
16. The apparatus of claim 15, further comprising a reactive gas
source in fluid communication with a space defined by the inner
chamber and the wafer support surface of the susceptor.
17. The apparatus of claim 15, further comprising a process
chamber, wherein the susceptor, the lift pin, the lift pin head,
and the inner chamber are in the process chamber.
18. The apparatus of claim 15, wherein the non-reactive gas source
is configured to establish a higher pressure at an area under a
bottom side of the susceptor than a pressure in the inner
chamber.
19. The apparatus of claim 14, wherein the upper portion of the
lift pin head is wider than the lift pin.
20. The apparatus of claim 14, wherein a lower portion of the lift
pin is external to the hole of the susceptor.
Description
RELATED APPLICATIONS
[0001] This application is a continuation application of U.S.
patent application Ser. No. 16/230,765, filed Dec. 21, 2018, now
U.S. Pat. No. 10,748,806 issued on Aug. 18, 2020, which is a
divisional application of U.S. patent application Ser. No.
13/929,297 filed on Jun. 27, 2013, U.S. Pat. No. 10,163,676 issued
on Dec. 25, 2018, all of which are incorporated herein by reference
in its entirety.
BACKGROUND
[0002] In semiconductor manufacturing, multiple layers (such as a
SiN layer, a high-K layer, a poly layer, etc.) are deposited on the
front side of a wafer, in which an adhesion layer (such as SiN)
plays an important role for adhering the other layers to the wafer.
During deposition of the layers, the layers are unintentionally
deposited on the backside of the wafer with little or no adhesion
layer. After the deposition of the layers, the wafer still needs to
undergo several subsequent processes, in which some processes may
cause a high stress difference between two adjacent layers, and
some processes with high thermal budgets may induce large thermal
stress in the layers. Such high stress difference and thermal
stress may result in backside peeling defects on the wafer,
especially on the region of the backside of the wafer on which
little or no adhesion layer is formed. The more the layers are
deposited on the backside of the wafer, the higher the peeling
defect failure rate will be. Therefore, the backside peeling
defects of the wafer can be avoided by preventing the layers from
being deposited on the backside of the wafer.
BRIEF DESCRIPTION OF THE DRAWINGS
[0003] For a more complete understanding of the present
embodiments, and the advantages thereof, reference is now made to
the following descriptions taken in conjunction with the
accompanying drawings, in which:
[0004] FIG. 1A is a schematic diagram showing a process chamber
with a susceptor for various embodiments;
[0005] FIG. 1B is a schematic diagram showing a non-reactive gas
flow pattern on a wafer support surface of the susceptor depicted
in FIG. 1A in accordance with some embodiments;
[0006] FIG. 2A is a schematic explosive view of an exemplary
susceptor depicted in FIG. 1A;
[0007] FIG. 2B is a schematic cross-sectional view of the susceptor
with a straight through hole in accordance with some
embodiments;
[0008] FIG. 2C is a schematic cross-sectional view of the susceptor
with a step through hole in accordance with certain
embodiments;
[0009] FIG. 3A-FIG. 3D are schematic diagrams showing exemplary
types of lift pin heads;
[0010] FIG. 4A is an inspection result of film deposition on the
backside of a wafer when conventional lift pin heads are used;
[0011] FIG. 4B is an inspection result of film deposition on the
backside of a wafer when lift pin heads with flow channel
structures shown in FIG. 3A are used;
[0012] FIG. 5 is a defect trend chart showing a backside peeling
defect trend when lift pin heads with flow channel structures shown
in FIG. 3A are used; and
[0013] FIG. 6 is a schematic diagram showing a multi-chamber
processing system in accordance with various embodiments.
DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS
[0014] It is understood that the following disclosure provides many
different embodiments or examples for implementing different
features of various embodiments. Specific examples of components
and arrangements are described below to simplify the present
disclosure. These are, of course, merely examples and are not
intended to be limiting. The present disclosure may repeat
reference numerals and/or letters in the various examples. This
repetition is for the purpose of simplicity and clarity and does
not in itself dictate a relationship between the various
embodiments and/or configurations discussed.
[0015] Terms used herein are only used to describe the specific
embodiments, which are not used to limit the claims appended
herewith. For example, unless limited otherwise, the term "one" or
"the" of the single form may also represent the plural form. The
terms such as "first" and "second" are used for describing various
devices, areas and layers, etc., though such terms are only used
for distinguishing one device, one area or one layer from another
device, another area or another layer. Therefore, the first area
can also be referred to as the second area without departing from
the spirit of the claimed subject matter, and the others are
deduced by analogy. Moreover, space orientation terms such as
"under", "on", "up", etc. are used to describe a relationship
between a device or a characteristic and another device or another
characteristic in the drawing. It should be noted that the space
orientation term can cover different orientations of the device
besides the orientation of the device illustrated in the drawing.
For example, if the device in the drawing is turned over, the
device located "under" the other devices or characteristics is
reoriented to be located "above" the other devices or
characteristics. Therefore, the space orientation term "under" may
include two orientations of "above" and "below".
[0016] The present disclosure is to establish a diffusion barrier
between a susceptor and a wafer placed on the susceptor to limit or
prevent film deposition on the backside of the wafer, such that
backside peeling defects of the wafer in the subsequent processes
can be reduced or avoided. The susceptor has through holes and lift
pins inserted in the through holes. Each lift pin has a lift pin
head coupled thereto for raising or lowering the wafer from or on
the susceptor. Embodiments of the present disclosure are directed
to forming grooves and/or holes on the lift pin heads of the lift
pins to intentionally allow a proper amount of gas to flow into the
backside of the wafer to form the diffusion barrier.
[0017] FIG. 1A is a schematic diagram showing a process chamber 200
with a susceptor 110 for various embodiments of the present
disclosure. The process chamber 200, such as an ALD (Atomic Layer
Deposition) chamber, disclosed herein is used as an example for
explanation, and embodiments of the present disclosure are also
applicable to other types of apparatuses. As shown in FIG. 1A, the
process chamber 200 includes the susceptor 110, an inner chamber
210 and non-reactive gas sources 140. The susceptor 110 has through
holes 112 and a wafer support surface (not labeled) on which a
wafer 100 can be placed. In each through hole 112, there are a lift
pin 130 and a lift pin head 120 coupled to the lift pin 130. The
lift pin 130 is operable to have a vertical degree of motion in the
through hole 112 so as to lift up or place the wafer 100 from or on
the susceptor 110 via the lift pin head 120 contacting the wafer
100. The lift pin head 120 has at least one flow channel structure.
The flow channel structure is used for directing non-reactive gas
from the non-reactive gas sources 140 to an area between the
susceptor 110 and the backside of the wafer 100.
[0018] In contrast to the reacting gas used for forming deposition
films, the gas supplied by the non-reactive gas sources 140 does
not participate in film forming reactions, such as nitrogen, inert
gas (for example, argon), etc. The non-reactive gas sources 140 are
configured to flow the gas to the bottom side 102 of the susceptor
110, and then the gas flows to the backside of the wafer 100
through the flow channel structure of each lift pin head 120 by
diffusion or injection. In some examples, the non-reactive gas
sources 140 are configured to flow the gas to an area under the
bottom side 102 of the susceptor 110, so as to establish a higher
pressure at the area under the bottom side 102 of the susceptor 110
than a pressure in the inner chamber 210 enclosing the wafer
support surface of the susceptor 110, such that the gas can be
diffused into the backside of the wafer 100 through the flow
channel structure of each lift pin head 120. In certain examples,
the non-reactive gas sources 140 are configured to inject the gas
to the flow channel structure of each lift pin head 120. The flow
rate of the gas should be well controlled not to move or vibrate
the wafer. In some embodiments, the pressure difference between the
area under the bottom side of the susceptor 110 and the inner
chamber 210 is about 0.1-0.2 torr, while the pressure in the
process chamber 200 is about 2-3 torr. While in operation, the
non-reactive gas sources 140 are configured to establish a
diffusion barrier on the backside of the wafer 100, and the
reacting gas passing through the front side of the wafer 100 to a
hot trap is blocked from entering the backside of the wafer, so as
to prevent film deposition on the backside of the wafer 100, thus
reducing or avoiding backside peeling defects for the wafer 100 in
the subsequent processes.
[0019] Referring to FIG. 1A and FIG. 1B, FIG. 1B is a schematic
diagram showing a non-reactive gas flow pattern on a wafer support
surface of the susceptor 110 in accordance with some embodiments.
To minimize the wafer 100 moving or vibrating, the gas establishing
the diffusion barrier on the backside of the wafer 100 is flowed in
a symmetric pattern with respect to a central axis of the susceptor
110.
[0020] As shown in FIG. 1B, three lift pin heads 120 are disposed
on the susceptor 110, and each lift pin head has five flow channel
structures, as signified by flow arrows 121. The flow channel
structures of all of the lift pin heads 120 are disposed
symmetrically around the central axis of the susceptor 110, so as
to provide a symmetric flow pattern. In some embodiments, the
number of the flow channel structures of each lift pin head 120 is
greater than two, such as three, five or any number that can enable
the flow channel structures of all of the lift pin heads together
to provide a symmetric flow pattern. On the other hand, the
non-reactive gas flow pattern of the present disclosure is not
limited to a symmetric pattern, and the flow channel structures may
be uniformly or non-uniformly distributed on one lift pin head 120,
as long as the wafer vibration and displacement caused by the gas
flow from the flow channel structures can be minimized or none.
[0021] As shown in FIG. 2A-FIG. 2C, three lift pin heads 120 and
three lift pins 130 are assembled through the through holes 112 of
the susceptor 110. The flow channel structure of each lift pin head
120 extends from a bottom surface 124 (i.e. the first surface) of
the lift pin head 120 which is at least partially exposed to a
bottom side 102 of the susceptor 110 through a side surface 126 or
a top surface 127 (i.e. a second surface) of the lift pin head 120
which is exposed to a top side 104 of the susceptor 110. In other
words, embodiments of the present disclosure are featured in
modifying the lift pin head 120 to form one or more flow channel
structures for directing a gas from the non-reactive gas sources
140 to an area between the susceptor 110 and the backside of the
wafer 100.
[0022] In general, there are two types of through holes 112. As
shown in FIG. 2B, the through hole is a straight through hole 112a.
In this case, the flow channel structure may be a groove or
penetrating hole running from the bottom surface 124 of the lift
pin head 120 through the side surface 126 or the top surface 127 of
the lift pin head. As shown in FIG. 2C, the through hole is a step
through hole 112b, in which the lift pin head 120 may contact a
floor 103 of the susceptor 110 to restrict gas flowing through the
through hole 112b. In this case, the groove or penetrating hole
(flow channel structure) of the lift pin head 120 has to be
appropriately formed to prevent the gas from being blocked by the
floor 103 of the susceptor 110. Embodiments of the present
disclosures are mainly to modify the lift pin head 120 to form a
flow channel structure for allowing non-reactive gas to pass
through the through hole 112 or the lift pin 130 and the flow
channel structure to the top side 104 of the susceptor 110. It is
noted that the applications of the embodiments do not need to
change the structures of other components in the process chamber
besides the lift pin head 120 and in some cases, the lift pin
130.
[0023] Hereinafter, several types of flow channel structures are
provided as examples for explanation, but embodiments of the
present disclosure are not limited thereto.
[0024] FIG. 3A-FIG. 3D are schematic diagrams showing exemplary
types of lift pin heads. In some embodiments, the lift pin head 120
has a flange around its sidewall. However, the lift pin head with
no flange is also applicable to embodiments of the present
disclosure, i.e. the lift pin head and the lift pin are of the same
outer diameter. As shown in FIG. 3A, a flow channel structure of a
lift pin head 120a is a groove 122a cut into a bottom surface 124a
and a small portion of width of a side surface 126a, such that
non-reactive gas may flow along a direction A1 to a wafer. Since
there is little or no room between the susceptor and the lift pin
head 120a, the non-reactive gas exiting from the groove 122a will
be guided by the susceptor towards the top side of the
susceptor.
[0025] As shown in FIG. 3B, besides the flow channel structure
similar to the one shown in FIG. 3A, a lift pin head 120b has
another two types of flow channel structures. One type of flow
channel structure is a groove 122b1 extending from a bottom surface
124b of the lift pin head 120b through a side surface 126b of the
lift pin head 120b to a top surface 127b of the lift pin head 120b,
such that non-reactive gas may flow along a direction B1 to a
wafer. The other type of flow channel structure is a penetrating
hole 122b2 running from the corresponding lift pin through the top
surface 127b of the lift pin head 120b. In this case, the
corresponding lift pin also has a penetrating hole aligned with the
penetrating hole 122b2, such that non-reactive gas may flow along a
direction B2 to a wafer.
[0026] As shown in FIG. 3C, a lift pin head 120c has two types of
flow channel structures. One type of flow channel structure is a
groove 122c1 cut into a bottom surface 124c and a large portion of
width of a side surface 126c, such that non-reactive gas may flow
along a direction C1 to a wafer. The other type of flow channel
structure is a groove 122c2 extending from the bottom surface 124c
through the side surface 126c to a top surface 127c of the lift pin
head 120c, such that non-reactive gas may flow along a direction C2
to a wafer.
[0027] As shown in FIG. 3D, a flow channel structure of a lift pin
head 120d is a combination of a groove 122d1 and a penetrating hole
122d2, in which the groove 122d1 is cut into a side surface 126d
and the penetrating hole 122d2 is formed in the groove 122d1. In
this case, the corresponding lift pin also has a penetrating hole
aligned with the penetrating hole 122d2, such that non-reactive gas
may flow along a direction D1 to a wafer.
[0028] FIG. 4A is an inspection result of film deposition on the
backside of a wafer when conventional lift pin heads are used. FIG.
4B is an inspection result of film deposition on the backside of a
wafer when lift pin heads with flow channel structures shown in
FIG. 3A are used. The film deposition is indicated by shadow areas
shown in the figures. Comparing FIG. 4A and FIG. 4B, the apparatus
using the lift pin heads with flow channel structures has much less
film deposition on the backside of a wafer than that using the
conventional lift pin heads. Thus, backside peeling defects of the
wafer in subsequent processes can be reduced or avoided.
[0029] FIG. 5 is a defect trend chart showing a backside peeling
defect trend when lift pin heads with flow channel structures shown
in FIG. 3A are used. At week t1, the lift pin heads with the flow
channel structures shown in FIG. 3A are used to replace the
conventional lift pin heads for production. As shown in FIG. 5, the
defect counts per wafer are greatly reduced and meet the defect
count goal at and after week t1.
[0030] FIG. 6 is a schematic diagram showing a multi-chamber
processing system 300 in accordance with various embodiments. As
shown in FIG. 6, the multi-chamber processing system 300 (such as a
cluster tool) includes multiple process chambers 200a-200f, in
which each of the process chamber s 200a-200f has the lift pin
heads with flow channel structures in accordance with the
aforementioned embodiments.
[0031] In accordance with some embodiments, the present disclosure
discloses an apparatus including a susceptor and a non-reactive gas
source. The susceptor has through holes and a wafer support
surface. Each through hole includes a lift pin and a lift pin head.
The lift pin has a vertical degree of motion in the through hole,
and is operable to lift up or place a wafer on the susceptor. The
lift pin head is disposed on the lift pin and has at least one flow
channel structure running from its first surface at least partially
exposed to a bottom side of the susceptor through its second
surface exposed to a top side of the susceptor. The non-reactive
gas source is configured to flow a gas to the bottom side of the
susceptor.
[0032] In accordance with certain embodiments, the present
disclosure discloses a system includes at least one apparatus, and
each apparatus includes a susceptor, a non-reactive gas source and
an inner chamber. The susceptor has through holes and a wafer
support surface. The inner chamber encloses the wafer support
surface of the susceptor. Each through hole includes a lift pin and
a lift pin head. The lift pin has a vertical degree of motion in
the through hole, and is operable to lift up or place a wafer on
the susceptor. The lift pin head is disposed on the lift pin and
has at least one flow channel structure running from its first
surface at least partially exposed to a bottom side of the
susceptor through its second surface exposed to a top side of the
susceptor wherein the lift pin. The non-reactive gas source is
configured to flow a gas to the bottom side of the susceptor.
[0033] Although the present embodiments and their advantages have
been described in detail, it should be understood that various
changes, substitutions and alterations can be made herein without
departing from the spirit and scope of the disclosure as defined by
the appended claims.
[0034] Moreover, the scope of the present application is not
intended to be limited to the particular embodiments of the
process, machine, manufacture, composition of matter, means,
methods and steps described in the specification. As one of
ordinary skill in the art will readily appreciate from the
disclosure, processes, machines, manufacture, compositions of
matter, means, methods, or steps, presently existing or later to be
developed, that perform substantially the same function or achieve
substantially the same result as the corresponding embodiments
described herein may be utilized according to the present
disclosure. Accordingly, the appended claims are intended to
include within their scope such processes, machines, manufacture,
compositions of matter, means, methods, or steps.
* * * * *